Differences between genders were examined for IGF-1, IGFBP-3, growth hormone, and testosterone undergoing bovine colostrum supplementation during two weeks of in-season training. Males (N = 10) and females (N = 9) were supplemented with 20 gm of bovine colostrum daily for two weeks. Blood samples were drawn four times over the duration of the study.

Females had significantly higher average IGF-1, IGFBP-3, and growth hormone readings than males, whereas males had higher testosterone readings. Both genders increased similarly in IGF-1 (19%) over the two weeks. IGFBP-3 decreased in both genders but growth hormone only decreased in females. Testosterone did not change in either group during the study.

Implication. Females respond differently to males with bovine colostrum supplementation. However, the IGF-1 factor response is similar in both groups. The decrease in growth hormone in females suggests the supplementation might be less than beneficial for females.